Push bench



W. MARTIN PUSH BENCH May 29, 1934.

Filed Sept. 23, 1930 Patented May 29, 1934 PATENT OFFICE PUSH BENCH Wilhelm Martin, Dusseldorf-Reisholz, Germany,

assignor to Pressand Walzwerk Aktiengesellschaft, Dusseldorf-Reisholz, Germany Application September 23, 1930, Serial No. 483,819 In Germany July 18, 1927 1 Claim. (01. 205-4 In the known processes for producing long tubes a previously punched hot metal block is successively pushed through a row of gradually narrowing draw rings by means of a rod-like man- 5 drel, so that the material of the metal block is drawn as a thin layer over the mandrel. In order to enable the mandrel to be also pushed through the last narrowest draw ring it is pushed forward by a long rod, the so called shaft rod, driven for m example by a long rack. During the production of very long tubes the mandrel and shaft rod must be protected against bending out, that issupported between the driving rack and the part of the bench bed carrying the draw rings, as this long metal rod, composed of the mandrel and the shaft rod forming an extension of the mandrel, must transmit heavy pressure forces and at the same time also overcome periodically occurring resistances.

In these known hot draw or thrust benches of this type, only the movement of the bench in the one direction is utilized for the drawing operation, the return movement of the bench being an idle movement,'so that really only half of the running time of a bench plant is utilized for producing work.

This invention relates to a hot drawor thrustbench plant for producing long tubes, which ensures a double output of the plant, as compared with commonly used plants. This effect is attained according to the invention in that a plurality of draw-benches or thrust-benches are connected to a common driving mechanism and at the same time the drawor thrust benches thus dependent upon the common drive are not provided in the manner hitherto often usual with guide parts for the mandrel or mandrel rod,

longitudinally shiftable in the draw-bench, but

with guide parts which are arranged stationary 40 in relation to the longitudinal direction of the bench and so shaped or so mounted on their bearing point in the bench bed in conformity with the mandrel movement, that they allow an unimpeded entrance of the machine elements (for example the rack) driving the mandrel shaft, if necessary suitably shaped and arranged for this purpose, into the part of the bench bed, which is situated in front of the drawing tool and traversed by the mandrel and mandrel shaft.

The invention is based on the known idea, to render possible the joining of a plurality of drawbenches also in such cases, in which, owing to the great length of the tubes to be produced and of the mandrels and mandrel shafts necessary therefor, it is not possible to do without their reliable guiding by means of separate guide elements.

In this arrangement of the individual drawbenches a specially reliable working of the benches is obtained, so that it is possible to couple a plurality of draw-benches in a simple manner without any risk that thereby breakdowns occur easily in the plant. Moreover, in the manner described it is possible to obtain a particularly steady running of the plant free from shocks and a minimum stressing of the driving mechanism.

According to the proposals of the invention very efiicient and reliable draw-bench plants are obtained for producing long tubes, idle running m of the driving mechanism being avoided at the same time, i. e. utilizing same to the best advantage. The invention also renders it possible, to increase the output of existing old draw-bench plants in a simple manner in retaining the existing driving mechanism without enlarging or reinforcing the same.

The manner in which the individual drawbenches to be united to one single plant, are connected to the common driving mechanism may vary in the individual cases, according to the requirements and prevailing conditions.

It is preferable to arrange and equip or utilize the draw-benches and their driving mechanism in such a manner that the one bench, or group of benches, does drawing work during the movement of thedriving mechanism in the one direction and the other bench, or group of benches, during the movement in the other direction. Thus, for example, a plurality of draw-benches can be connected to a common rackor chain- 'drive in such a manner, that each end of the rack operates a draw-bench. Instead of this arrangement instances may also be imagined, in which for example two draw-benches are connected side by side to one and the same end of the rack. Such a possibility may occur, when rebuilding existing benches in cases, Where it is possible, by the use of stationary guide parts of the type already mentioned, to reduce the power consump. tion of the individual benches, as compared with the former use of heavy longitudinally shiftable guide parts, so that the driving device, which is unnecessarily strong for the new conditions, is suflicient for the simultaneous working stroke 105 of two draw-benches.

If it is borne in mind, that already the use of the stationary guide parts is known which enables a doubling of the output of a draw bench of the known old construction (with heavy guide 110 parts reciprocating in the draw-bench along long distances), it is possible to obtain a further increase of the output, in all a fourfold increase of the output, of the old. plant through the above mentioned simultaneous doubling of the number of draw-benches connected to the old driving mechanism in preserving the driving mechanism which was formerly just sufiicient, all this in the simplest possible manner.

Finally it is possible, through a further pair of draw-benches coupled to the other end of the rack, to also utilize the idle movement of the bench for producing work so that, for example a reconstructed draw-bench ofknown type originally with guide part reciprocating in the bench bed, may be brought to even eight times the output, without having to change the driving device or to select a greater driving force. The arrangement may also be such, that merely one draw-bench, or group of draw-benches, is driven directly from the driving mechanism, whereas the other draw-bench, or group of drawbenches, is driven through the intermediary of suitable devices, for example a chain pull, from the directly driven draw-bench or group of di'aw' benches. Such a construction will offer particularly simple constructional conditions in cases, where a second draw-bench is to be connected with an already existing draw-bench, in the meaning of the invention for the purpose of doubling the output.

A further feature of the invention consists in that the draw-benches united to form a combined plant can be individually operated independently the one of the other, and the plant may be so arranged, that it is possible to simultaneously produce therewith tubes of different dimensions sideby side. The means employed herefor consist firstly of clutches, by means of which the draw-benches can be engaged and disengaged individually or in groups, and secondly of change gearings, which enable to alter the stroke and working speed of the individual benches, as is most suitable for the production of the different types of tubes in the various instances.

Through the use of reversing gears, which; if necessary, can be united with any existing change gears, it is possible to develop independent individual operation of the benches, if each draw-bench is further provided with an independent control arranged near same. These controls can be made dependent the one of the other by a suitable blocking, such as is already known for other purposes in machine construction, in such a manner that only a maximum number of existing draw-benches can be engaged simultaneously for the driving period. In this case, in spite of the freedom in the individual attendance of the draw-benches, it is possible 'to prevent a sudden overloading of the driving engine, and to utilize an engine with a lower efiiciency than would be necessary otherwise for supplying the total power required for all the draw-benches.

Particularly great economy is obtained with the draw-bench plant arranged according to the invention if the draw-benches are so arranged that they can be attended from one single furnace plant.

Several embodiments of the invention are i1- lustrated diagrammatically by way of example in the accompanying drawing:-

Fig. 1 shows in top plan view a form of construction with two draw-benches fitted with stationary guide elements and driven by a common rack.

Fig. 2 shows a similar view to Fig. 1, the guide rollers mounted on transverse carriages.

Fig. 3 is a part side elevation of Fig. 1.

Fig. 4 shows in top plan view a modified form of construction, the benches being arranged side by side.

Figs. 1, 2' and 3 show a draw-bench plant, in which two draW-benches a and b of the already mentioned construction, are driven from a common rack c. The operation of the draw-bench a coincides with the idle movement of the drawbench b and inversely, so that at each outward movement and at each return movement of the rack c actuated by a driving mechanism 01 a tube is produced.

The guiding of the mandrels m and the mandrel shafts n is efiected for example by guide rollers o and p, p, arranged in pairs and so shaped and arranged, that the racks 0 driving the mandrels m by means of the shafts n, can be moved thereover, as is shown for example in Figs. 3 and 5. If the draw-benches are to work with regular changing of the mandrel rods between every two operations, the guide rollers p may for example be mounted on transverse carriages (1, by means of which these guide rollers can be shifted a certain distance-prior to the insertion of a mandrel min order to enable the insertion of this mandrel m. r are the known draw-rings for shaping the tube from the blank x, which is pushed through the same by means of the mandrel m. Fig. 2 shows another form of construction of the new draw-bench plant. In this instance two draw-benches are provided, each equipped with one rack c, a respectively. Both racks c and c are driven from-a driving mechanism d, for example an electric motor, the gearing of which engages by means of a pinion in the racks. The other details of this form of construction of the invention correspond to the already described details of the form of construction shown in Figs. 1 and 3.

I claim:

A thrust draw bench for producing long seamless tubes, comprising in combination a mechanical driving means, a pair of draw benches arranged parallel the one to the other one on each side of said driving means and driven so that when one draw bench is forcing a tube through a die the other draw bench is carrying out its idle movement, each bench comprising a man- .drel, a shaft for said mandrel, a machine part driven by said common driving means adapted to drive said mandrel and said shaft, and a plurality of guide pieces adapted to guide said mandrel and said shaft, some of said guide pieces being arranged stationary and all of said guide pieces adapted to permit a free passage of said driving machine part between them.

WILHELM MARTIN. 

